/**
 * @author zhouzhiheng98@foxmail.com 2020-08-03 17:58:26
 */
public class Assertion {
    public static void main(String[] args) {
        double x = Math.abs(-123.45);
        //如果想让assert起作用，需要给Java虚拟机传递-enableassertions（可简写为-ea）参数启用
        assert x <= 0 : " must >= 0";
        System.out.println(x);
    }
}
